In motor vehicle cooling systems for cooling engine coolant, refrigerant vapor and engine oil it has been desirable to locate either an oil cooler or a refrigerant condenser unit at a location upstream of the inlet surface of the radiator for removing heat from the coolant system for an liquid cooled engine. Examples of such systems are set forth in U.S. Pat. Nos. 3,479,834 and 4,138,857.
Such location exposes the tube passes of the refrigerant condenser and/or oil cooler to ram air flow as the vehicle is driven in a forward direction. Furthermore, such location causes the engine fan to draw cooling air across the condenser while the vehicle is stopped or slow moving and the engine is idling. As a consequence the condenser is operative to condense refrigerant gas to a liquid which is then directed across an expansion valve for controlling the flow of refrigerant into a refrigerant evaporator. A circulating fan draws air flow across the evaporator for cooling the interior or passenger compartment of a motor vehicle in a known manner. Likewise a continual flow of cooling air is directed across the oil cooler.
While the forward or upstream location of the refrigerant condenser is a favorable location for providing continual air flow across the tube passes of the condenser and/or oil cooler, such refrigerant condensers and oil coolers have separate air centers and the radiator has separate air centers which can cause undesirable contracttion, expansion, contraction cycles in the inlet airstream for cooling the separate components of combination radiator and condenser apparatus for motor vehicles. Such pressure cycles in the inlet airstream result in an increased pressure drop that will reduce the cooling effectiveness of the inlet airstream of the vehicle.
In the past such reduction in cooling effectiveness has been compensated by providing a slightly oversized frontal area in the radiator or the condenser could be located laterally of the radiator so as not to retard air flow therethrough. An example of a laterally offset condenser is set forth in U.S. Pat. No. 3,447,596.
Present vehicle design constraints have reduced the available space for such oversized radiators or for such offset condenser configurations.
Additionally, in future automobile air conditioning systems high cost alternative refrigerants are being proposed. In order to minimize the amount of such refrigerant required to effectively cool a vehicle engine compartment it will be desirable to reduce the size of the condenser to reduce the total volume of refrigerant in the system but without reducing the cooling capacity of the condenser.
In order to avoid such design constraints an object of the present invention is to provide a combined radiator and condenser apparatus wherein the tube passes of both the radiator and the condenser have the same air centers for defining a single air flow path through both the radiator and the condenser which will not increase the pressure drop across the radiator and condenser as the inlet airstream of a motor vehicle is directed thereacross.
In prior combination radiator and condenser apparatus no solution has been proposed which will enable a condenser and a radiator to be located in limited space confines of a motor vehicle without adversely affecting the flow of coolant air flow across one or both of the separate condenser and radiator units.